Double-acting hydraulic actuators are known in the prior art and are widely used. Typical examples of such actuators are described in the document EP 1488996 to the same applicant.
The present invention is directed to hydraulic cylinders, regardless of their specific arrangement, whether unbalanced cylinders or of any other type known in the prior art.
The different components of actuating cylinders known in the prior art are widely spread and tested, in order to optimize operation of the cylinders.
Although these devices accomplish their function in a satisfactory manner, they have a number of drawbacks.
One of the most widespread drawbacks is the difficulty in assembling both the cylinder on the watercraft, and the individual cylinder components that have to be assembled together.
The assembling is a matter that only experts can accomplish, therefore, even in emergency cases or damage cases, a common user is hardly able to act on the cylinder.
Moreover, the parts of prior art known cylinders that is most subjected to wear is the head, since it is the component most subjected to mechanical stresses.
The head has to slide on the rod while guaranteeing the seal of the fluid flowing in the steering devices. Therefore the head, subject to a number of fatigue cycles, tends to wear and this inevitably causes the fluid to leak from the chambers of the cylinder to the outside.
Since such undesired condition creates a malfunction, the head is the component that is replaced most often, even if the replacement regards only a part thereof or even the gaskets that have been damaged.
This further leads to drawbacks from the economic standpoint, since it requires an excessively high expense for the operator, he/she being forced to change the entire head even if a very small part of it is damaged.
Therefore, there is the unsatisfied need in the prior art to provide a double-acting hydraulic actuating cylinder, for hydraulic steering devices, particularly for marine outboard motors, that can be easily mounted on the watercraft and that has components that can be easily replaced, improving the performance and cost-related characteristics.